Pitch-coking process and product



n um from its j duction of a coke of low-ash or low impurity JOSH BECKER, OF IPITTSB'UBGH, PENNSYLVANIA, ASSIGNOR TO THE KOPPERS COM- 0F PITTSBURGH PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA PITCH-BORING PROCESS AND PRODUCT Ito Drawing. Application tiled Quota-16,1918, -Serial No. 330,988. Renewed march 21, 1924.

This invention relates generally to the cok ing of liquefiable bituminous materialand has fora primary object a' production of coke. in a manner which substantially eliminatesexa cess intumesce'nce and ebullition ofthe material during the coking process, and to produce a coke for em loyment in metallurgical furnaces, which co e is formed-from a mixture 0t pitch and a. material that is substanvl0 tially infusible at coking temperatures and whose residuum in the resultant coke is hemologous with the material to be recovered in such furnaces. The process is, for instance, adapted for making coke for use in the making of electrodes for electric furnaces, especially as employed in the recovery of alumiores and contemplates the proa as regards residues other than those homoloi a q gous with the materialto be recovered in such urnaces. Although the invention is especial- 1y applicable to the-coking of pitch, itmay readily be applied to other liquefiable-bitumi- I nous materials, and itwill be understood that the invention is not-limited-to the specific process nor to the 'specifioapplicationherein described as an illustrative example.

' In carrying outthe invention a proportion of pitch or other liquefiable bituminous material, is mixed with a proportion of a metallic compound hat is infusible at coking temperature and checks foaming of the pitch and yet does'not leave in the finished coke a residuum foreign to, nor'introduce ob ect1onable impurities into the material electrolytically treated in the electric furnace in which electrodes made of such coke are employed. The invention is of particular importance in type and subjected in the oven tothe required 7 coking heat. The coking process is carried on efiiciently, without the usual difiiculties encountered in the coking of ordinary pitch, on other analogous liquefiable bituminous materials, which when subjected to the high temperatures necessary for coking, frequently boil and intumesce violently. This foaming and intumescing of pitch materials in coke ovens results in amechanical loss of a large proportion of the coke and produces conditionyin thev oven or retort which seriously interfere with the closures and outlets of the oven or, retorh The coke resulting, from a mixture 'ofjfpitch' and bauxite, for example, will 'be ac ighly homogeneous product, and of great value'in the manufacture of carbon electrodes'gior aluminium furnaces which require the use of coke substantially ash free or of low impurity as regards residues other than those homologous with the bacterial to be recovered in such furnaces. This follows from the fact that the non-carbon residuum in such bauxite pitch coke will be the same material, bauxite, that is electrolytically treated in such furnaces.

An advantageous ap lication of the above stated discovery is as ollows: A proportion of ordinary pitch, or other liquefiable bituminous material is thoroughly mixed with a subthe production of coke for the manufacture stantially equal proportion of bauxite. This mixture-may then be charged into an oven and coked. Instead of employing raw bauxite in the mixture, a proportion of the coke produced from a similar mixture of pitch and bauxite, according to the above process, may be employed. This would result in a cyclic process for the manufacture of pitch coke. or example, a proportion of the coke produced from a mixture of pitch and bauxite, may be set aside and utilized for the production of a subsequent similar "mixture. This would have the advantage that the coke produced would contain a relatively hi her carbon content than would be the case i the coke be produced from a mixture of pitch and raw bauxite. Coke produced from a mixture of pitch and a substantially equal proportion of bauxite contains approximately 32% carbon and approximately 68% alumina. On the other hand coke produced from a mixture of pitch and a substantially equal proportion of coke formed from a like previous mixture of coke and bauxite contains over carbon and less than 50% alumina. The coke of higher carbon content is of course more desirable when employed for the manufacture of carbon electrodes for aluminium furnaces, inasmuch as it will not disintegrate as rapidly as the coke containing the higher alumina content.

The term pitch is used in the appended claims in a generic rather than a technically specific sense, and to include ebulliently liqueiiable bituminous materials of the general nature of pitch; and my invention includes the treatment of such materials to produce a coke substantially ash-free or of low impurity as regards undesirable residues and yet remedy the coking difiiculties hereinabove indicated.

The processes of the invention may be practiced in various ways, other than the particular embodiment that has been described for purposes of illustration, and still be Within the scope and subject matter of the claims hereinafter made. 9

I claim 1. In a pitch coking process; mixing a substantially equal proportion of pitch with a substantially equal portion of bauxite; and gokiing the mixture; substantially as speci- 2. In a pitch coking process for the production of coke for employment in electrodes of electrolytic furnaces; mixing pitch with a proportion of a material that is substantially infusible at coking temperatures and Whose residuum in the resultant coke comprises alumina; and coking themixture; substantially as specified.

3. A process which comprises coking a mixture containing pitch and a suihcient proportion of bauxite to prevent substantial foaming of the mixture during coking thereof.

4. A process which comprises coking a mixture containing pitchand a sufiicient proportion of material comprisin alumina to prevent substantial foaming o the mixture during coking thereof.

5. In a cyclic process for the manufacture I of pitch coke, coking a mixture containing pitch and a suflicient proportion of bauxite to prevent substantial foaming of the mixture during coking thereof, making a mixture containing at least a portion of the resultant coke and pitch, and coking said mixture.

6. In a cyclic process for the manufacture of pitch coke, coking a mixture containing pitch and a sufficient proportion of material comprising alumina to prevent substantial foaming of the mixture during coking thereof, making a mixture containing at least a portion of the resultant coke and pitch, and coking said mixture.

7. In a cyclic process for the manufacture of pitch coke, mixing a substantially equal proportion of pitch with a substantially equal proportion of alumina, coking the mixture, making a mixture containing at least a proportion of the resultant coke and pitch, and coking said mixture.

8. A mixture containing pitch and a sufficient proportion of bauxite to prevent substantial foaming of the mixture during COk', ing thereof.

9. A mixture containing pitch and a sufiicient proportion of material'comprising alumina to prevent substantial foaming of the mixture during coking thereof.

10. Coke made by coking a mixture of pitch and bauxite and substantially ash-free as regards residues other than bauxite.

11. Coke made by coking a mixture of pitch and material comprising alumina and substantially ash-free as regards residues other than alumina.

12. A process which comprises coking a mixture containing substantially ash-free bituminous material liquefiable by heat and a sufiicient proportion of bauxite to prevent substantial foaming of the mixture during coking thereof.

13. A process which comprises coking a mixture containingsubstantially ash-free bituminous material liquefiable by heat and a sufficient proportion of material comprising alumina to prevent substantial foaming of the mixture during coking thereof.

14:. A mixture containing substantially ash-free bituminous material liquefiable by heat and a sufficient proportion of bauxite to prevent substantial foaming of the mixture during coking thereof.

15. A mixture containing substantially ash-free bituminous material liquefiable by heat and'a sufficient proportion of material comprising alumina to prevent substantial fgaming of the mixture during coking there- 0 16. Coke made by coking a mixture of substantially ash-free bituminous material liquefiable by heat and bauxite and substantially ash-free as regards residues other than bauxite. I

17. Coke made b coking a mixture of sub stantially ash-free ituminous material liquefiable by heat and material comprising alumina and substantially ash-free as regards residues other than alumina.

In testimony whereof I have hereunto set my hand this 7th day of October, 1919.

JOSEPH BECKER. 

